Table of Contents
Advertisement
ABB REL 356 Current Differential Protection
All of the relay circuitry, with the exception of the input isolation transformers and first-line surge protection, are mounted
on the inner chassis, to which the front panel is attached. The outer chassis has a backplate, which is a receptacle for
all external connections, including the digital communication interface. Two optional FT-14 switches are mounted in the
two peripheral areas of the outer chassis. The FT-14 switches permit convenient and safe disconnection of trip, ac and
dc circuits, and provide for injection of test signals.
REL 356 Modules
The inner and outer chassis, together, contain standard modules, plus the optional relay output board. The backplane
module and digital communication interface (DCI) are connected to the backplate of the outer chassis. The remaining
modules are attached to the inner chassis:
·
Interconnect module
·
Relay output modules
·
Contact input module
·
Microprocessor module
·
Display module
·
Power supply module
·
Analog input module
·
Modem module for 9600 bps audio tone channel version
·
CODEC (coder-decoder) module for 56/64 kbps digital communication
Hardware Structure
The basic hardware consists of:
·
Input transformers for analog signals (currents only, or currents and voltages)
·
A front-end filter, multiplexer and A/D converter of those input signal
·
One CPU for analog input sampling, Fourier computations, operator interface and non-volative data storage
·
One CPU for protection functions, contact input interface, control output interface and communication interface
·
Status inputs for logic operations
·
Output contacts for control of external devices
·
EPROM for program storage
·
EEPROM for settings and fault-data storage
·
Modem or CODEC module for protection communication
1-4
Product Overview and Specifications
Advertisement
Table of Contents
